Display system, display method in the system and display program for using social graph information of users of multiple applications

ABSTRACT

When retrieving information relating to another user of a different SNS, the CVR of an SNS can be effectively increased by displaying a social graph. According to the invention, by means of a social graph display program (API), user identifying information corresponding to user-to-user relationship information meeting predetermined conditions can be extracted by searching a database of information related to the other users of application programs A-C, in accordance with identifying information of a user A who has made a friend request. Thus the application program A displays, as candidates for the friend request, users corresponding to user identifying information returned from the social graph display program (API).

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.16/736,733, filed Jan. 7, 2020, which is a continuation of U.S.application Ser. No. 16/020,281, filed Jun. 27, 2018 (the entirecontents incorporated herein by reference), which is a continuation ofU.S. application Ser. No. 14/419,498, filed on Jun. 15, 2015, now U.S.Pat. No. 10,037,325, issued Jul. 31, 2018, and is based upon and claimsthe benefit of priority to International Application No.PCT/JP13/071270, filed on Aug. 6, 2013 and from the prior JapanesePatent Application No. 2012-174341 filed on Aug. 6, 2012. The entirecontents of each of these documents are incorporated herein byreference.

TECHNICAL FIELD

The present invention relates to a display system and to a displaymethod and a display program in the same system.

BACKGROUND

In recent years, social networking service (hereinafter, referred to as“SNS”) technologies have been widely used as represented by Twitter(Registered Trademark), Facebook (Registered Trademark), and the like.In such an SNS, for example, users can exchange messages such as inchats or the like and establish friend relationships on the network.Thereby, connections between the users are created. Under suchcircumstances, in recent years, it is well known that the concept of asocial graph to depict such connections between users has been proposedin Facebook.

As represented by Facebook described above, such a social graph isconstructed by behavior of users in a predetermined SNS in general. Atechnology of collecting social graph information through different webservices, creating a synthetic social graph from the collected socialgraph information, and delivering the social graph has been disclosed(Patent Document 1).

Moreover, in recent years, an operating environment (applicationplatform) such as an application program interface (API) to be operatedon a web browser has been provided onto an SNS. Application softwarecreated with this as platforms are collectively referred to as socialapplications, and games in the social applications are referred to associal games.

In particular, social games do not require dedicated client software butcan be played with only a web browser and an account of an SNS, and themost remarkable characteristics of social games include combination withthe original communication function of an SNS. The games themselves aremainly easily playable in a short period of time not only on a personalcomputer but also on a feature phone, a smart phone, and the like.

PRIOR ART DOCUMENTS Patent Documents

-   Patent Document 1: Japanese Laid-Open Patent Publication No.    2010-146415

SUMMARY

However, in Patent Document 1, social graph information of the same userin other web services including different SNSs cannot be retrieved. Inan SNS, an increase in a conversion rate (CVR), which indicates anincrease in users who use the SNS, is important. However,conventionally, there is no system capable of retrieving the socialgraph information of the same user, including different SNSs. Thus,users who use the SNS cannot efficiently be increased.

The same applies to service platforms including a plurality of gameapplications. There has been no system that retrieves social graphinformation of the same user in a plurality of game applications.

Accordingly, it is an objective of the present invention to provide adisplay system capable of efficiently increasing the CVR of an SNS byretrieving information on a relationship with other users of a serviceplatform including a plurality of application programs or userinformation of other users, extracting identifying information of theretrieved information on the relationship with other users or theretrieved user information of other users, and displaying social graphinformation corresponding to the extracted identifying information ofother users on a client terminal, and to provide a display method and adisplay program in the same system.

In accordance with the first invention of the present disclosure, adisplay system is provided that includes: a storage device that ismanaged for each of application programs and stores, in association, atleast either information on a relationship with another user orinformation relating to use of a corresponding application program; ameans that, in response to a predetermined event request from theapplication program, retrieves the information on the relationship withanother user or the information relating to the use of the correspondingapplication program, the information meeting a predetermined conditioncorresponding to identifying information of a user who has made thepredetermined event request regarding the application programs of thestorage device, and extracts another user identifying information of theretrieved information on the relationship with another user or theretrieved information relating to the use of the correspondingapplication program; and a means that returns the extracted another useridentifying information to the application program from which thepredetermined event request has been made, thereby displayinginformation corresponding to the extracted another user identifyinginformation on a client terminal of the user who has made thepredetermined event request.

According to the present invention, the CVR of an SNS is efficientlyincreased by retrieving the information on the relationship with otherusers of the service platform including a plurality of applicationprograms or the user information of other users, extracting theidentifying information of the retrieved information on the relationshipwith other users or the retrieved user information of other users, anddisplaying the information corresponding to the extracted identifyinginformation of other users on the client terminal.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram for illustrating an environment in which a socialgraph display system according to one embodiment of the presentinvention is used.

FIG. 2 is a diagram showing one example of a configuration of a servergroup 2 in the embodiment of the present invention.

FIG. 3 is a diagram showing a configuration of a server 10 that performsoperations of the social graph display system according to theembodiment of the present invention.

FIG. 4 is a diagram showing social graph information database 22.

FIG. 5 is a diagram for illustrating social graph information.

FIG. 6 is a flowchart for illustrating social graph display processing.

FIG. 7 is a flowchart for illustrating processing by a social graphdisplay program (API) 23 and an application program A in a case ofmaking a friend request.

FIG. 8 is a flowchart for illustrating processing by the social graphdisplay program (API) 23 and an application program B in a case ofmaking a friend invitation.

FIG. 9 is a diagram for illustrating an image of the social graphdisplay system according to the present embodiment.

FIG. 10 is a diagram for illustrating creation of relationship valueinformation of the social graph information database and the like in thesocial graph display system according to the present embodiment.

FIG. 11 is a diagram showing one example of a view of the friendinvitation.

FIG. 12 is a diagram showing one example of a view in a case ofretrieving other users with a user level (user information) of theprogram.

FIG. 13 is a diagram showing one example of a view in a case ofretrieving other users with a total game playing time (user information)of the program.

DETAILED DESCRIPTION

One embodiment of the present invention will now be described withreference to the drawings.

Hereinafter, with reference to the drawings, a social graph displaysystem according to the embodiment of the present invention will bedescribed.

FIG. 1 is a diagram for illustrating an environment in which the socialgraph display system according to the embodiment of the presentinvention is used.

As shown in the drawing, in a network 1 such as the Internet, a servergroup 2 and a computer 3 and a mobile phone 4 that use the social graphdisplay system according to the embodiment of the present invention areconnected to the network 1 via an access point 5 or a base station 6.

The server group 2 is a computer for realizing the social graph displaysystem according to the embodiment of the present invention, and may berealized by one computer or may be formed by a plurality of computerssuch as a web server, a processing server, and a database server foreach of the functions thereof, and in the embodiment of the presentinvention, may be formed in any form.

The computer 3 includes a general desktop computer as well as a mobilecomputer, a laptop computer, and a tablet type terminal.

The mobile phone 4 includes a smart phone and a feature phone, andserves as a mobile phone to be operated on an operating system such asAndroid (Registered Trademark) and iOS (Registered Trademark), forexample.

FIG. 2 is a diagram showing one example of the configuration of theserver group 2 in the embodiment of the present invention.

As shown in the drawing, for example, the server group 2 is formed by afront-end server group 2-1, a database server group 2-2, and a batchserver group 2-3.

The front-end server group 2-1 is in charge of formatting of executionoutputs of various types of processing that can be executed uponreceiving a request for communication with a client. For example, a webserver and the like are included.

The database server group 2-2 records user identifying information, userinformation, changes, social graph information, and the like. Forexample, the database server group 2-2 is a processing server thatperforms core processing of social networking service processing.

The batch server group 2-3 periodically obtains data from the databaseserver group 2-2, performs periodic processing, and records the resultsin the database server group 2-2.

In the present embodiment, to facilitate illustration, a case whereoperations are performed on one server 10 will be described. However, asdescribed above, a configuration of the server is not limited to this.

FIG. 3 is a diagram showing the configuration of the server 10 thatperforms the operations of the social graph display system according tothe embodiment of the present invention.

As shown in the drawing, the server 10 has a bus 11 to which a CPU 12, acommunication unit 13, a memory 14, and a storage device 15 areconnected.

The CPU 12 works together with a social graph display program (API) 23according to the embodiment of the present invention that is stored inthe storage device 15, to perform social graph display processingaccording to the embodiment of the present invention as well as handlingcontrol of the entire server 10.

The communication unit 13 handles the control of communication withexternal devices such as clients via the network 1.

The memory 14 is used as a work area or the like required at the time ofexecuting the social graph display program (API) 23.

The storage device 15 stores programs required for the social graphdisplay processing and data, and is, for example, a high-capacitystorage device such as a hard disk drive (HDD), an optical disc drive, aDVD, and a MO. The storage device 15 stores an operating system (OS) 21,a social graph information database 22, and the social graph displayprogram (API) 23.

The OS 21 is a program for realizing basic functions of the server 10.

The social graph information database 22 manages the data used in thesocial graph display processing operated by the social graph displayprogram (API) 23. In the present embodiment, the identifying informationof the user is managed for each application program (application programID), and user-to-user relationship information is managed for each pieceof identifying information of the user.

In addition, although the case has been described in which theidentifying information of the user is managed for each applicationprogram and user-to-user relationship information is managed for eachpiece of identifying information of the user, the present invention isnot limited to this. For example, the identifying information of theuser may be managed for each piece of user-to-user relationshipinformation and the application program may be managed for each piece ofidentifying information of the user.

FIG. 4 is a diagram showing the social graph information database 22. Asshown in the drawing, user identifying information 31, user information32, and user-to-user relationship information 33 are managed for each ofapplication programs A to C.

The “user identifying information 31” is identifying informationcommonly used in the application programs A to C. Therefore, the sameuser identifying information displays the same user, and the userinformation 32 and user-to-user relationship information 33 thereof areheld for each of the application programs A to C.

The “user information 32” is information relating to an individualattribute of the user or use of a predetermined application. Forexample, when the application program A is a social networking game, theuser information is the user level, items, the number of coins, thenumber of medals, cards, and the like. The user information sometimesbecomes an object of retrieval at the time of displaying a social graph.

The user information 32 can include the following information, forexample.

The user level of other users of a corresponding application program,the user level to be set for each application program

-   -   Total game playing time of other users of a corresponding        application program, the time to be set for each application        program (for example, one day, one week, one month)    -   Game start time points of other users of a corresponding        application program, the time points to be set for each        application program (for example, the game was started in        September 2012)    -   Game hours of other users of a corresponding application        program, the hour to be set for each application program (for        example, 10:00 to 14:00 on weekdays)    -   Charging timing of other users of a corresponding application        program, the timing to be set for each application program (for        example, one day, one week, one month)    -   Completion rate of other users of a corresponding application        program, the rate to be set for each application program (for        example, quest completion rate and the number of boss beating        characters)    -   Corresponding desired item list to be set for each application        program (for example, particular SSR cards registered in a wish        card list in a card game)    -   The number of times of posting of other users to the same        message board as that of the user, the number to be set for each        application program    -   Regional information, birthday, age, gender, hobbies, blood        type, Chinese astrological zodiac sign, and profile image post        of other users to be set for each application program    -   The number of footprints of other users who is a friend of the        user, the number to be set for each application program    -   History information to be set for each application program such        as a news article, column, and the like of other users (for        example, in the fields of gourmet, shopping, beauty, sports,        leisure, media, entertainment, living, life, school, public        service, and the like)    -   Ranking of other users of a corresponding application program,        the ranking to be set for each application program    -   Game genre registration number of My Game of other users, the        number to be set for each application program (for example, the        registration number of two for a role-playing game). In        addition, the game genre includes, for example, dating,        training/simulation, board, card, sports, racing, action,        timing, puzzle, adventure, education/quiz, gambling, and the        like)    -   Avatar use rate of other users to be set for each application        program

The “user-to-user relationship information 33” is information serving asan object of retrieval at the time of displaying the social graph, theinformation on a relationship with other users. For example, as shown inFIG. 5 , information such as “affinity,” “compatibility,” and “friend”with other users may serve as the user-to-user relationship information.

“Affinity” is determined for each user, for example, by the number oftimes of a conversation (chats or the like) with a user A.“Compatibility” is determined for each user, for example, by a characterattribute of the user, items, and the like. Regarding “friend,” a userwho approves a friend request from the user A or who makes a friendrequest to the user A, the request having been approved by the user A isa “friend.” In addition, the examples described above are only oneexample. The user-to-user relationship information is not limited tothis as long as the information displays the relationship with otherusers. For example, the case has been described in which after a userwho makes a friend request to the user A, the request having beenapproved by the user A is a “friend.” However, even when the request isnot approved, he/she may become a “friend.” In this case, definition ofthe friend between the users is calculated with use of a threshold value(indicating a relationship between the affinity and the compatibility)determined on the server in advance, and friend approval is made. Sincethe relationship between the affinity and the compatibility regardscalculation on the server, description thereof will be omitted here.

In such a way, a user is retrieved through the application programsbased on at least one piece of the user-to-user relationship informationand the user information, so that the social graph can be displayed.Thus, the CVR of the application programs can be improved. In addition,for example, as shown in FIG. 5 , the user-to-user relationshipinformation for each application program may have “relationship valueinformation” and the user identifying information may be extracted basedon this relationship value information. The relationship valueinformation is information on the relationship between the user andother users.

This “relationship value information” is calculated by combiningparameters (user information, user-to-user relationship information(such as affinity with other users, compatibility, the number offriends, the number of times of trading, the number of times ofrequests, and the number of times of e-mailing)) of the user for eachapplication program (application program ID). For example, therelationship value information is calculated by multiplying each of theparameters by a predetermined coefficient. Next, this relationship valueinformation is normalized (calculated by standard deviation and anaverage value) and stored. Next, a distribution of the calculatedrelationship value information is obtained and the relationship valueinformation in the same application program is normalized. Next, basedon the normalized relationship value information, a filter for obtainingthe relationship value information at the time of inserting and changingthe data is created (S41). In addition, processing of S41 isperiodically repeated (for example, once a day) and the distribution ofthe relationship value information is updated.

At the time of inserting/updating the user data (user ID, userinformation, user-to-user relationship information), the filter createdin S41 is used and various types of data are converted into datanormalized in accordance with the distribution of the relationship valueinformation (S42). Then, based on this converted data, the normalizedrelationship value information is stored in S41.

In addition, although the case has been described in which thenormalized relationship value information is stored in S41, thenormalized relationship value information may be stored or recorded.

The user data is inserted/updated, for example, as shown in FIG. 10 , ina case where the friend request is approved in the application program Aor a friend invitation in the application program A is made to a user inanother application and the invited user starts the application A.

In addition, the relationship value information stored in the database22 of each of the application programs is combined for each user andnormalized (S51). Then, based on this normalized relationship valueinformation, highly related users having the relationship valueinformation meeting a predetermined condition are retrieved.

The social graph display program 23 is an API of the applicationprograms A to C, and works together with the CPU 12 so as to realize thesocial graph display processing according to the embodiment of thepresent invention.

Next, construction of the relationship value information included in theuser-to-user relationship information of the social graph informationdatabase 22 will be described with reference to FIG. 10 .

First, in a case where the social graph information database 22 is newlyconstructed, the user ID, the user information 32, and the user-to-userrelationship information 33 are constructed for each application programas shown in FIG. 4 .

Among the above, the relationship value information included in theuser-to-user relationship information 33 is calculated by combiningparameters (user information, user-to-user relationship information(such as affinity with other users, compatibility, the number offriends, the number of times of trading, the number of times ofrequests, and the number of times of e-mailing)) of the user for eachapplication program (application program ID). This calculatedrelationship value information is normalized (calculated by standarddeviation and an average value) and stored.

Next, the social graph display processing related to a friend request inthe social graph display system according to the embodiment of thepresent invention will be described with reference to a flowchart ofFIG. 6 .

In addition, the description will begin from a state where there is norelationship between the user A and the user B and the user A and theuser B have neither started the application program A nor theapplication program B yet.

First, both of the user A and the user B start the application program A(Steps A-1, B-1). Next, the user A makes a friend request to the user Bin the application program A (Step A-2).

In a case where the friend request is made, processing shown in FIG. 7is performed by the social graph display program (API) 23 and theapplication program A.

That is, when a friend request is made by the application program A(S21), the social graph display program (API) 23 searches the socialgraph information database 22 of the application programs A to C basedon the identifying information of the user A, who has made the friendinvitation, retrieves the social graph information meeting apredetermined condition, and extracts the user identifying informationof the retrieved social graph information (S22).

The “predetermined condition” is, for example, to sort in the order ofhigh “affinity” (the number of times of a conversation) and extract theuser identifying information within a fixed range or the like. The“predetermined condition” may be set by combining a plurality of piecesof user information, may be set by combining the user information andthe user-to-user relationship information, or may be calculated byperforming some processing.

In a case where the friend request is made based on the relationshipvalue information, the relationship value information stored in thedatabase 22 of each of the application programs is combined for eachuser and normalized. Then, based on this normalized relationship valueinformation, the highly related users having the relationship valueinformation meeting the predetermined condition are retrieved.

Next, the social graph display program (API) 23 returns the extracteduser identifying information to the application program A (S23), and theapplication program A displays users corresponding to the useridentifying information returned from the social graph display program(API) 23 as candidates of the friend request (S24). The user selects theuser displayed to make the friend request among the users displayed asthe candidates of the friend request in the application program A (S25).Thereby, the friend request is made. The user B is assumed to beselected in this description.

When the friend request is made, the social graph display program (API)23 notifies the user B of the fact that the friend request has been madevia the application program A. The user B approves the friend requestfrom the user A in the application program A (Step B-2).

When the request is approved, the user A establishes a friendrelationship with the user B and the user B establishes a friendrelationship with the user A in the application program A (Steps A-3,B-3). Specifically, the application program A adds “friend with the userB” to the social graph information of the user A, and adds “friend withthe user A” to the social graph information of the user B.

Next, a case of inviting a friend will be described.

The user B starts the application program B (Step A-4). Next, the user Amakes an invitation to the user B in the application program B (StepA-5).

In a case where the friend invitation is made, processing shown in FIG.8 is performed by the social graph display program (API) 23 and theapplication program B.

That is, when a friend invitation is made by the application program B(S31), the social graph display program (API) 23 searches the socialgraph information database 22 of the application programs A to C basedon the identifying information of the user A, who made the friendrequest, retrieves the social graph information meeting a predeterminedcondition, and extracts the user identifying information of theretrieved social graph information (S32).

The “predetermined condition” is, for example, to sort and extract thefriends of other application programs in the order of a high matchingrate (indicating in how many application programs a certain friendexists).

In a case where a friend invitation is made based on the relationshipvalue information, the relationship value information stored in thedatabase 22 of each of the application programs is combined for eachuser and normalized. Then, based on this normalized relationship valueinformation, highly related users having the relationship valueinformation meeting the predetermined condition are retrieved.

Next, the social graph display program (API) 23 returns the extracteduser identifying information to the application program B (S33), and theapplication program B displays users corresponding to the useridentifying information returned from the social graph display program(API) 23 as candidates of the friend invitation (S34). The user selectsa user to make a friend invitation among the users displayed as thecandidates of the friend invitation in the application program B (S35).Thereby, the friend invitation is made. The user B is assumed to beselected in this description.

FIG. 11 is a diagram showing one example of a view of the friendinvitation. As shown in the drawing, friends in other applicationprograms are displayed. This display is displayed in order of highlyrelated users based on predetermined criteria such as the above matchingrate or the relationship value information. When a friend invitation ismade, the social graph display program (API) 23 notifies the user B ofthe fact that the friend invitation has been made via the applicationprogram B. The user B approves the friend invitation from the user A inthe application program B (Step B-4).

When the invitation is approved, the user A establishes a friendrelationship with the user B and the user B establishes a friendrelationship with the user A in the application program B (Steps A-6,B-5). Specifically, the application program B adds “friend with the userB” to the user-to-user relationship information of the user A, and adds“friend with the user A” to the user-to-user relationship information ofthe user B.

FIG. 9 is a diagram for illustrating an image of the social graphdisplay system according to the present embodiment. As shown in thedrawing, users respectively exist in the application programs A to D. Ina case of making a friend invitation, based on the social graphinformation managed for each of the application programs A to D, theuser identifying information is retrieved and extracted based on apredetermined condition, and the characters of users corresponding tothe user identifying information extracted as candidates of the friendinvitation are displayed as a social graph. On the right side of FIG. 9, one example of the social graph displayed on the terminal is shown.The display method is not limited to this.

In addition, FIG. 11 shows a case of inviting a friend. However, theuser may be invited based on other social information. In the aboveembodiment, a case where the user is retrieved based on the user-to-userrelationship information or the relationship value information isdescribed. However, the user may be retrieved based on the userinformation.

FIG. 12 is a diagram showing one example of a view in a case ofretrieving other users with a user level (user information) of theprogram. FIG. 13 is a diagram showing one example of a view in a case ofretrieving other users with a total game playing time (user information)of the program.

Therefore, according to the present embodiment, the user can beretrieved through the application programs based on the user-to-userrelationship information or the user information, and the social graphcan be displayed. Thus, the CVR of the application programs can beimproved.

The relationship value information can be weighed for each applicationprogram. Thus, at the discretion of a system administrator, the CVR ofthe application programs can be more finely controlled.

In addition, although only the friend invitation has been described forpurposes of illustration, the present invention is not limited to this.For example, in a case of a game system of a strategy game and the like,cooperation in battles is considered. In this case, an invitation of afriend whose cooperation is desired and the like are included.

Several embodiments of the present invention have been described.However, these embodiments are provided as examples with no intention tolimit the scope of the invention. These novel embodiments can beimplemented in various other modes, and various omissions, replacements,and changes can be made within the range not departing from the gist ofthe invention. These embodiments and modifications thereof are includedin the scope and the gist of the invention and included in the inventiondescribed in the claims and the range of equivalents.

Also, the method described in the embodiments can be stored in arecording medium such as a magnetic disk (floppy (Registered Trademark)disk, hard disk, and the like), an optical disc (CD-ROM, DVD, MO, andthe like), and a semiconductor memory (ROM, RAM, flash memory, and thelike) as a program that can be executed by a computing machine(computer), or can be transferred and distributed by a communicationmedium. In addition, the program to be stored on the medium alsoincludes a setting program for configuring a software means (includingnot only execution programs but also tables and data structures) to beexecuted by and in the computing machine. The computing machine forrealizing the device reads the program recorded in the recording medium,or constructs the software means by the setting program according tocircumstances and executes the above processing by controllingoperations with this software means. In addition, the recording mediumdescribed in the present specification includes not only the one fordistribution but also a storage medium provided inside the computingmachine or in a device connected via a network such as a magnetic diskand a semiconductor memory.

DESCRIPTION OF THE REFERENCE NUMERALS

1 . . . Network, 2 . . . Server group, 3 . . . Computer, 4 . . . Mobilephone, 5 . . . Access point (AP), 6 . . . Base station, 21 . . .Operating system, 22 . . . Social graph information database, 23 . . .Social graph display program (API)

The invention claimed is:
 1. A system comprising: at least one serverconfigured to receive, via a first application program, a friend requestfrom a first client terminal of a first user for a second user,register, in the first application program, a friend relationshipbetween the first user and the second user, in response to receivingapproval of the friend request from a second client terminal of thesecond user, receive, via a second application program, a request fromthe first client terminal of the first user to display candidate usersto be invited to the second application program, identify at least oneuser registered as being in a friend relationship with the first user inthe first application program as a candidate user, transmit informationindicating the candidate user to the first client terminal of the firstuser, receive, via the second application program, an invitation to thesecond application program from the first client terminal of the firstuser, the invitation targeting the second user, and register, in thesecond application program, a friend relationship between the first userand the second user, in response to receiving approval of the invitationfrom the second client terminal of the second user.
 2. The systemaccording to claim 1, wherein the at least one server is configured toidentify the at least one user registered as being in the friendrelationship with the first user in the first application program as thecandidate user, based on user information associated with use of thefirst application program by the at least one user.
 3. The systemaccording to claim 2, wherein the user information includes a user levelof the at least one user of the first application program.
 4. The systemaccording to claim 2, wherein the user information includes usage timeof the first application program by the at least one user.
 5. The systemaccording to claim 1, wherein the at least one server is configured totransmit the information indicating the candidate user to the firstclient terminal of the first user to display, at the first clientterminal, the candidate users in an order associated with apredetermined condition.
 6. The system according to claim 1, wherein theat least one server is configured to transmit the information indicatingthe candidate user along with identification information of anapplication program used by the candidate user and associated with thefirst user.
 7. The system according to claim 1, wherein the at least oneserver is configured to transmit the information indicating thecandidate user along with usage information of an application programused by the candidate user and associated with the first user.
 8. Thesystem according to claim 1, wherein the at least one server isconfigured to identify the at least one user registered as being in thefriend relationship with the first user in the first application programas the candidate user, based on relationship value information betweenthe first user and the at least one user, the relationship valueinformation being combined and normalized, and based on the normalizedrelationship value information, a highly related user having therelationship value information meeting a predetermined condition beingretrieved as the candidate user.
 9. The system according to claim 1,wherein the at least one server is configured to identify the at leastone user registered as being in the friend relationship with the firstuser in the first application program as the candidate user, byexecuting an application program interface (API) program of the firstapplication program and the second application program.
 10. A methodperformed by a system, the method comprising: receiving, via a firstapplication program, a friend request from a first client terminal of afirst user for a second user; registering, in the first applicationprogram, a friend relationship between the first user and the seconduser, in response to receiving approval of the friend request from asecond client terminal of the second user; receiving, via a secondapplication program, a request from the first client terminal of thefirst user to display candidate users to be invited to the secondapplication program; identifying at least one user registered as beingin a friend relationship with the first user in the first applicationprogram as a candidate user; transmitting information indicating thecandidate user to the first client terminal of the first user;receiving, via the second application program, an invitation to thesecond application program from the first client terminal of the firstuser, the invitation targeting the second user; and registering, in thesecond application program, a friend relationship between the first userand the second user, in response to receiving approval of the invitationfrom the second client terminal of the second user.
 11. The methodaccording to claim 10, wherein the identifying identifies the at leastone user registered as being in the friend relationship with the firstuser in the first application program as the candidate user, based onuser information associated with use of the first application program bythe at least one user.
 12. The method according to claim 11, wherein theuser information includes a user level of the at least one user of thefirst application program.
 13. The method according to claim 11, whereinthe user information includes usage time of the first applicationprogram by the at least one user.
 14. The method according to claim 10,wherein the transmitting transmits the information indicating thecandidate user to the first client terminal of the first user todisplay, at the first client terminal, the candidate users in an orderassociated with a predetermined condition.
 15. The method according toclaim 10, wherein the transmitting transmits the information indicatingthe candidate user along with identification information of anapplication program used by the candidate user and associated with thefirst user.
 16. The method according to claim 10, wherein thetransmitting transmits the information indicating the candidate useralong with usage information of an application program used by thecandidate user and associated with the first user.
 17. A non-transitorycomputer readable medium including a program, which when executed by asystem, causes the system to: receive, via a first application program,a friend request from a first client terminal of a first user for asecond user; register, in the first application program, a friendrelationship between the first user and the second user, in response toreceiving approval of the friend request from a second client terminalof the second user; receive, via a second application program, a requestfrom the first client terminal of the first user to display candidateusers to be invited to the second application program; identify at leastone user registered as being in a friend relationship with the firstuser in the first application program as a candidate user; transmitinformation indicating the candidate user to the first client terminalof the first user; receive, via the second application program, aninvitation to the second application program from the first clientterminal of the first user, the invitation targeting the second user;and register, in the second application program, a friend relationshipbetween the first user and the second user, in response to receivingapproval of the invitation from the second client terminal of the seconduser.
 18. The non-transitory computer readable medium according to claim17, wherein identifying of the at least one user registered as being inthe friend relationship with the first user in the first applicationprogram as the candidate user, is based on user information associatedwith use of the first application program by the at least one user. 19.The non-transitory computer readable medium according to claim 18,wherein the user information includes a user level of the at least oneuser of the first application program.
 20. The non-transitory computerreadable medium according to claim 18, wherein the user informationincludes usage time of the first application program by the at least oneuser.